1. Field of the Invention
The present invention relates to an automatic hooking apparatus for hooking and lifting an object, and also to a ship cargo handling gear suitable for use in handling heavy cargo such as pig iron ingot or iron scrap pieces between a pier and a ship alongside the pier.
2. Description of the Related Art
Handling of cargo such as pig iron ingots or iron scrap pieces has been conducted mainly by magnet-type cargo gear. Pig iron ingots or iron scrap pieces are usually transported by a vehicle such as a truck to a pier and are stacked on the pier. The pig iron ingots or iron scrap pieces are then attracted by a solenoid suspended by a wire of a crane, and the boom of the crane is swung to bring the cargo to a position above the ship's hull. The wire is then extended to lower the solenoid and the solenoid is de-energized to release the cargo. In some cases, other cargo holding means such as ropes or nets are used but the use of such means is only seldom.
The conventional cargo handling work relying upon a solenoid is quite inefficient because the amount of the scrap pieces lifted at a time is as small as one ton, due to limited attracting force of the solenoid. In addition, since the cargo is held merely by electromagnetic attracting force, it may dangerously drop due to an impact during, for example, swiveling of the boom of the crane, causing a risk of injury or damaging of the ship or loss of the cargo into the sea. Furthermore, since the cargo such as iron scrap pieces are temporarily landed on the pier from the transportation vehicle, dust is generated to deteriorate the working environment.